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Bug #49819 STDOUT losing data with posix_isatty()
Submitted: 2009-10-09 12:50 UTC Modified: 2010-05-18 09:25 UTC
Avg. Score:4.0 ± 0.0
Reproduced:0 of 0 (0.0%)
From: cschneid at cschneid dot com Assigned: mike
Status: Closed Package: Streams related
PHP Version: 5.2, 5.3, 6 OS:
Private report: No CVE-ID:
 [2009-10-09 12:50 UTC] cschneid at cschneid dot com
The PHP streams for stdin, stdout and stderr are seekable which results in php_stream_flush() and seek being called on it.

For some reason php_stream_flush() fails to actually write the data while still calling seek and resetting the stream position.

Suggested solution:
- Find out why php_stream_flush() fails and fix it (I don't know enough about it)
- Mark (some? all?) stdio streams as PHP_STREAM_FLAG_NO_SEEK in sapi/cli/php_cli.c (see patch)
- Mark stdio streams as PHP_STREAM_FLAG_NO_SEEK in ext/standard/php_fopen_wrapper.c

Reproduce code:
php -r 'echo "hello1\n"; posix_isatty(STDOUT); echo "hello2\n";' >out; cat out

Expected result:

Actual result:


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 [2009-10-09 12:54 UTC] cschneid at cschneid dot com
--- sapi/cli/php_cli.c  (revision 289412)
+++ sapi/cli/php_cli.c  (working copy)
@@ -565,6 +565,10 @@
        s_err->flags |= PHP_STREAM_FLAG_NO_CLOSE;

+       s_in->flags  |= PHP_STREAM_FLAG_NO_SEEK;
+       s_out->flags |= PHP_STREAM_FLAG_NO_SEEK;
+       s_err->flags |= PHP_STREAM_FLAG_NO_SEEK;
        s_in_process = s_in;

        php_stream_to_zval(s_in,  zin);
 [2009-10-11 09:41 UTC]
Could reproduce with PHP 5.3-HEAD.
 [2010-03-09 01:22 UTC]
-PHP Version: 6SVN-2009-10-09 (SVN) +PHP Version: 5.2, 5.3, 6
 [2010-05-18 09:25 UTC]
Automatic comment from SVN on behalf of mike
Log: * fixed bug #49819: STDOUT losing data with posix_isatty()
 [2010-05-18 09:25 UTC]
-Status: Open +Status: Closed -Assigned To: +Assigned To: mike
 [2010-05-18 09:25 UTC]
This bug has been fixed in SVN.

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